Standard cargo containers are well known in the shipping art and are used throughout the world to transport goods by ship, rail, and truck. The containers comprise elongated box-like parallelepipedal structures. The dimensions of the containers are governed by International Standards Organization (ISO) specifications, and include an 8.5 foot height, an 8 foot width, and various lengths such as 20 feet and 40 feet. The eight corners of the containers have standard hollow corner blocks or castings which accept lifting and mounting connectors by which the container can be lifted or secured in place.
Cargo containers are most effectively utilized when they are fully loaded with goods during the shipping process. However, periodic worldwide economic conditions can occasion a shipping imbalance. For example, the 1997-1998 "Asian economic crisis" has resulted in thousands of containers traveling from Asia to the United States fill, and returning to the orient empty or "dead headed". On the return trip the empty containers both constitute wasted shipping volume, and since they are vertically stacked above decks, also present a wind-resisting surface which necessitates a slowing of the transport vessel. As much as two or three additional days can be added to a Pacific crossing. The wind-resistance problem is exacerbated by the fact that the empty containers cause the ship to ride higher in the water.
The present invention is directed to mitigating the abovementioned problems by providing a vertically collapsible container. The collapsible feature results in a shorter container stack which presents less wind resistance. Alternatively, more containers can be stacked thereby lowering the ship in the water and reducing the wind-resistance problem.
Examples of existing collapsible cargo containers include U.S. Pat. No. 3,966,075 which illustrates a receivable cargo container which can be cooperatively arranged with a standard cargo container in order to reduce "dead heading" operations by as much as 50%. The receivable cargo container slides into the end of the standard cargo container. U.S. Pat. No. 4,177,907 comprises a collapsible shipping container having hinged walls which fold together, thereby reducing the volume of the container. U.S. Pat. No. 4,355,732 discloses a folding container wherein two ends fold onto a base. U.S. Pat. No. 4,360,115 depicts a sectional multi-purpose cargo container which has provision for optional individual use or plural interlocked use. Two container halves are one-half the height of a normal container, and may be joined together to serve as a conventional container, or may be used separately to carry bulk raw materials. U.S. Pat. No. 5,370,256 includes a collapsible container. The height of the walls can be adjusted by sliding the sides. A lid is removably mounted to the walls. U.S. Pat. No. 5,111,950 comprises a shipping container which has a pallet base with four upstanding corner posts. A box-shaped cover is removed during the loading of cargo upon the pallet, and installed after the cargo is loaded. U.S. Pat. No. 5,170,901 shows a transportable construction element in the form of a container. The device has at least one hinged panel capable of pivoting between a closed position and an open position swung outwards, and an internal structure. U.S. Pat. No. 5,257,830 consists of a collapsible freight and storage container which has internal gears for lifting and lowering the top. Accordion style walls are utilized to accommodate the expanded and collapsed configurations. U.S. Pat. No. 5,501,333 discloses a collapsible container having a base, side wall and cap. When the container is collapsed, the cap can engage the base so that a container of reduced size is formed. The side walls are folded during the collapsing process. U.S. Pat. No. 5,611,449 illustrates a foldable container comprising a floor, a roof, and at least two side walls. Each of the side walls is connected with the floor through link members forming a connection between the edge side and the floor and the lower edge side of respective side walls.